Noone U.S. Pat. No. 3,043,426 discloses black water clarificatiion using a refuse filter which may be any conventional suitable filter preferably a drum type filter. The refuse collecting on the filter having an ash content of as high as 70% or more is scrapped off and discharged.
Halvorsen U.S. Pat. No. 4,248,697 discloses an oil agglomeration process wherein an oil is mixed with coal slurry which is then agglomerated and screened.
Keller, Jr. et al U.S. Pat. No. 4,186,887 discloses a process for recovering coal. The process uses a fluoro carbon agglomeration agent during milling of raw coal with water having thickener.
Capes et al U.S. Pat. No. 4,033,729 discloses a method of separating inorganic material from coal. A high portion of inorganic materials content is removed from coal by providing the coal as a suspension with a liquid hydrocarbon oil, mixing an aqueous agglomerating liquid comprising water with the suspension and subsequently separating the ash from the remainder.